Public safety agencies, including the Utah Highway Patrol, Carbon sheriff's office, Helper fire and rescue and the county HAZMAT team set up a command post near a tanker truck rollover on U.S. Highway 191. According to Incident commander Jason Llewelyn, the hazard from the spill was caused by 55,000 pounds of ammonium nitrate prill that came close to mixing with diesel fuel also carried by the truck. The HAZMAT team called a vacuum truck out of Salt Lake City to assist in cleaning the mess, which reportedly threatened a nearby water source. Llewelyn indicated that the incident, which happened at approximately 10 a.m. on Feb. 19, closed the highway until nearly 2 a.m. the following day.